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Understanding the Role of Sensory-Target Ankle Rehabilitation Strategies (STARS) in Chronic Ankle Instability

Musculoskeletal injury, such as chronic ankle instability, are a source of life-long disability and reduced physical activity. As such, EXSS scientists are focused on understanding ways to restore normal functional following musculoskeletal injury. We are pleased to welcome Dr. Erik Wikstrom to our team of EXSS scientists who are focused in this area. This week we highlight Dr. Wikstrom’s work, which highlights the importance of targeting the sensory system as part of a comprehensive rehabilitation strategy to improve function and restore balance in those suffering from chronic ankle instability.

Why did you do this study?

Ankle sprains are the most common injuries associated with physical activity and athletic participation, accounting for approximately 60% of all injuries that occur during interscholastic and intercollegiate sports. In 2010 alone, over 1 million ankle sprains were seen in U.S. Emergency Departments and resulted in $1.2 billion in health care charges. Further, at least 1 out of every 3 individuals who sprain their ankle will go on to suffer from a condition called Chronic Ankle Instability (CAI). CAI is characterized by recurrent ankle sprains, episodes of giving way, and a number of other structural and neuromuscular alterations. These alterations decrease function, cause an individual to be less physically active, and increase the risk of post-traumatic ankle osteoarthritis.

The cause of CAI remains unknown but evidence suggests that an ankle sprain causes the sensory receptors around the foot/ankle complex to send inaccurate information to the central nervous system (CNS). As a result, the CNS then generates altered movement patterns and, over time, these alterations result in impaired function. Traditionally, treatment and rehabilitation strategies for CAI have focused solely on addressing the observed alterations with little attention paid to the role of sensory inputs in the regulation of function. However, it may be possible to stimulate sensory receptors in order to reduce the alterations associated with CAI and subsequently improve function in this patient population. Manual therapies, such as ankle joint mobilizations, plantar massage, and stretching, are believed to target specific sensory inputs and represent a practical and affordable treatment option for all health care providers. However, no one had yet determined the effectiveness of targeting sensory inputs in order to improve patient outcomes or function in those with CAI. Therefore, the purpose of the study was to explore the effects of sensory-target ankle rehabilitation strategies (STARS) on subjective and objective outcomes and self-reported function in those with CAI.

What did you do and what did you find in this study?

We measured balance, ankle joint range of motion, and self-reported function in 80 physically active adults with CAI at three different universities. These were individuals who sustained on average 5 ankle sprains in their lifetime and almost 6 episodes of giving way within just the last 3 months. Subjects were then randomized to 4 groups that received 6, 5-minute treatments based on their respective group assignment over a 2-week period. Groups received either ankle joint mobilization, plantar massage, calf stretching, or a control condition (no treatment). While each treatment resulted in a unique response pattern across the tested outcomes, they all caused significant improvements in patient outcomes and function compared to the control condition. These improvements were still present 1-month after the treatment sessions ended.

How do these findings impact the public?

These findings suggest that manual therapies that target and manipulate specific sensory information can improve outcomes as well as function in those with CAI. The brevity of the treatments, the absence of equipment needed to perform the treatments, and opportunity for individuals to self-treat adds to the impact that these manual therapies could have at treating CAI related outcomes and improving function. Future research that combines sensory-targeted interventions with traditional rehabilitative exercises is needed to determine if an even greater impact on function in those with CAI can be achieved.